He said: "Thanks to their selfless actions, this despicable individual has received a lengthy prison sentence and deportation upon his release, which I hope reassures others to come forward in similar circumstances with information that can assist with a conviction."

Siwan Hayward, Transport for London's deputy director of enforcement and on-street operations, added: "We care about our passengers and every journey they make on our transport network. We, alongside the police, are committed to tackling any form of unwanted sexual behaviour on our network."